A commonly known problem with motor-driven trucks of the type described is that the operator's sight within the operating range of the truck is essentially limited owing to the lifting stand and its different accessories laying in front of him. Even if the operator moves to the side in the limited space in his cab, he cannot with his eyes get satisfactory contact with all places in front of the lifting stand where an object is to be handled with a lifting yoke or forks. From inter alia the safety aspect such working conditions are extremely unsatisfactory. Moreover the handling is delayed.
SE B 348 172 describes a vehicle which is especially intended for side directed loading and is provided with an operator's cab which is displaceable in the latitudinal direction of the vehicle so that the operator can place the cab in a side position where he better can survey the load and its handling with the forks located at the central portion of a longitudinal side. Thus, the operator's cab is moved only in a horizontal plane in a straight transverse path and only a part of the forks and load can be surveyed when these are located at a level under the operator's cab.
Also GB A 1 216 592 relates to a vehicle which is especially intended for side directed loading where the operator's cab of the vehicle is movable in a vertical plane in a straight path or alternatively in an arc-shaped path. Also in this case the operator's possibility to survey the load and forks will be limited.
In an article in the Swedish journal "Ny Teknik, Teknisk Tidskrift, 1984:48, page 29", a fork truck is described of the type which supports a front lifting stand on one end thereof where the operator's cab can be moved in a vertical plane in a straight path so that the operator can place the cab at a desired height level where he better can survey the load and its handling with the forks positioned at one short side. However, this possibility to place the operator's cab is not sufficient since the truck in addition thereto has to be provided with a TV-camera on the top of the lifting stand and a monitor in the operator's cab so that forks and load can be surveyed. However, the combination of TV-camera and vertically movable operator's cab gives no possibility to survey the forks and load from the side.
EP A 0 113 335 describes a motor vehicle to be used especially in agriculture. The motor vehicle is provided with an operator's cab which is movable horizontally in a straight path in the longitudinal direction of the vehicle and in a straight path in the latitudinal direction of the vehicle and in a vertical plane in an arc-shaped path as well. For this purpose the vehicle has a stationary longitudinal stand and a transverse stand which is suspended in parallelogram link arms and movable along the stationary stand. The transverse stand supports the operator's cab via a carriage by which the operator's cab can be moved on the link-suspended stand in the latitudinal direction of the vehicle. By means of the stand suspended in parallelogram link arms the operator's cab can be placed by a pivoting movement in different height positions, however, the distance between the uppermost and lowest positions will be comparatively short owing to constructional considerations to be taken. Thus, the length of the link arms has to be limited depending on the great stresses on the bearings of the link arms, particularly when the vehicle is driven on un uneven surface. The principle according to this patent specification is therefore not applicable to trucks having front lifting stand where it is desired to displace the operator's cab to such a high level that the operator can see above the top portion of the lifting stand or its lifting yoke, i.e. a displacement from a lower position to an upper position a distance of one or more meters taking into account stability problem.